CVE-2026-63519

Analyzed Analyzed - Analysis Complete

Heap-based Buffer Overflow in Microsoft Office

Publication date: 2026-08-11

Last updated on: 2026-08-13

Assigner: Microsoft Corporation

Description

Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-08-11

Last Modified

2026-08-13

Generated

2026-09-01

AI Q&A

2026-08-12

EPSS Evaluated

2026-08-30

NVD

CVE-2026-63519

EUVD

EUVD-2026-56424

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	365_apps	*
microsoft	365_apps	*
microsoft	office_2019	*
microsoft	office_2019	*
microsoft	microsoft_365	*
microsoft	office_2021	*
microsoft	office_2021	*
microsoft	office_2021	*
microsoft	office_2024	*
microsoft	office_2024	*
microsoft	office_2024	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-122	A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

Attack-Flow Graph

Executive Summary

This is a heap-based buffer overflow vulnerability in Microsoft Office. It allows an unauthorized attacker to execute arbitrary code on a local system by exploiting a flaw in memory handling.

Detection Guidance

Detection requires monitoring for unusual memory corruption patterns or crashes in Microsoft Office processes. Check for heap-based buffer overflow indicators in Office applications logs or crash dumps. Use tools like Windows Event Viewer to inspect application crashes related to Office processes.

Impact Analysis

An attacker could exploit this to run malicious code on your system, potentially stealing data, installing malware, or taking control of your computer. It requires user interaction, such as opening a specially crafted file.

Compliance Impact

This vulnerability allows unauthorized code execution, which could lead to unauthorized access to sensitive data. This may violate compliance requirements under GDPR (data protection) and HIPAA (health information security) if exploited.

Mitigation Strategies

Apply the latest security updates from Microsoft Office as soon as possible to patch the heap-based buffer overflow vulnerability.

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